ABSTRACT
The parts we see are not the real parts. ;x(Sx! ,Rx) To contest the soundness (not the validity) of this argument Reid would have
needed to make a case either for taking some minimally visible or tangible points to be real points or for some sort of demonstrative or regular connection between at least some sets of minimally sensible points and real magnitudes. Where angular magnitudes are concerned, making such a case is easy. But, as Berkeley had already pointed out (NTV 62) the prospects for doing the same with minimally sensible points are dim. In the Treatise Hume had maintained that our minimal perceptions must be adequate representations of the smallest possible parts of extension, for the plausible reason that they have no parts and that nothing could be smaller than a thing that has no parts (T 1.2.2.1). But he had also maintained that our minimal perceptions can often be (and so far as we know are always) revealed by experience to be inadequate representations of vastly more compound and complex objects (T 1.2.1.5). As we approach an object, parts that appeared as minimal points begin to appear as variously shaped compounds of a number of points. Often, these points are differently colored as well. As a consequence, the view of the same object from different distances can exhibit markedly different numbers, shapes, arrangements, and colors of parts. While the angular magnitude of the whole varies in accord with sine laws, the appearance of the thing that subtends the angle is dependent on us and its changes from distance to distance cannot be anticipated simply by applying sine laws. The angle is merely a useful fiction employed to measure the size of a mental image that is in fact at no distance from us.
